This homey recipe from The Pioneer Woman can easily be done a day ahead and chilled until ready to bake.
1 loaf cinnamon raisin bread
Butter, for greasing the baking pan
8 whole eggs
2 cups whole milk
½ cup heavy cream
1 cup sugar
2 teaspoons ground cinnamon
2 tablespoons vanilla extract
8 tablespoons cold butter, cut into pieces
½ cup flour
½ cup packed brown sugar
1 teaspoon ground cinnamon
¼ teaspoon salt
½ cup raisins
1. Cut bread into ¼-inch slices, then overlap the slices in rows in a well-buttered baking dish. Whisk together the eggs, milk, cream, sugar, vanilla, and cinnamon, then pour the mixture evenly over all the pieces of bread, soaking the bread as much as possible.
2. To make the topping, combine the butter, flour, brown sugar, cinnamon, and salt in a bowl and cut it all together with a pastry cutter. Stir in the raisins. Sprinkle the topping all over the casserole. Cover the pan with foil and refrigerate it for several hours or overnight.
3. Preheat the oven to 350°. Bake the French toast for 45 minutes to 1 hour for a softer texture, or longer for a firmer, crisper texture. Cover with foil for the first 30 minute of baking, then remove it for the remaining baking time. Serve individual helpings with butter and warm syrup